title: Lipid droplet metabolism.
abstract: OBJECTIVE
  With the realization that lipid droplets are not merely inert fat storage organelles, but highly dynamic and actively involved in cellular lipid homeostasis, there has been an increased interest in lipid droplet biology. Recent studies have begun to unravel the roles that lipid dropletss play in cellular physiology and provide insights into the mechanisms by which lipid droplets contribute to cellular homeostasis. This review provides a summary of these recent publications on lipid droplet metabolism.
  
  
  RESULTS
  Perilipins have different preferences for associating with triacylglycerol (TAG) or cholesteryl esters, different tissue distributions, and each contributes to lipid metabolism in its unique way. Cell death-inducing DFF45-like effector proteins are not only involved in lipid droplet expansion, but also in the cellular response to stress and lipid secretion. Lipid droplets undergo an active cycle of lipolysis and re-esterification to form microlipid droplets. TAG synthesis for lipid droplet formation and expansion occurs in the endoplasmic reticulum and on lipid droplets, and TAG transfers between lipid droplets during lipid droplet fusion. Lipid droplets interact with the endoplasmic reticulum and mitochondria to facilitate lipid transfer, lipid droplet expansion, and metabolism.
  
  
  CONCLUSIONS
  Lipid droplets are dynamically active, responding to changes in cellular physiology, as well as interacting with cytosolic proteins and other organelles to control lipid homeostasis.
authors.affiliation: aVeterans Affairs Palo Alto Healthcare System, Palo Alto bDivision of Endocrinology, Stanford University, Stanford, California, USA.
authors.forename: Victor K
authors.initials: VK
authors.lastname: Khor
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Shen
authors.forename: Fredric B
authors.initials: FB
authors.lastname: Kraemer
mesh_terms: D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins / Q000378:metabolism; D016923:Cell Death; D002788:Cholesterol Esters / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D050356:Lipid Metabolism / Q000502:physiology*; D008066:Lipolysis; D008928:Mitochondria / Q000378:metabolism; D015388:Organelles / Q000378:metabolism; D000070778:Perilipin-1; D010750:Phosphoproteins / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins; D002788:Cholesterol Esters; D000070778:Perilipin-1; D010750:Phosphoproteins; D011506:Proteins; D014280:Triglycerides; C109664:caspase-activated DNase inhibitor